Breast cancer surveillance following ovarian cancer in BRCA mutation carriers.

OBJECTIVES: BRCA 1 or 2 mutation carriers have increased risk of developing breast cancer (BC) and serous epithelial ovarian cancer (EOC). The incidence of BC over time after EOC is unknown. Optimal BC surveillance for BRCA mutation carriers following EOC has not been defined. METHODS: A multi-institutional retrospective chart review was performed. Patients with BRCA -associated EOC diagnosed between 1996 and 2016 were followed for an average of 80 months. Women with previous bilateral mastectomy were excluded; women with prior BC and an intact breast were included. Descriptive statistics, Chi Square, and univariate survival analysis were performed. RESULTS: 184 patients with BRCA -associated EOC were identified. Eighteen (10%) were diagnosed with BC a median of 48 months following EOC. Two (1%) with prior BC developed contralateral BC and 16 (9%) developed primary BC. The majority of BC (55%) was diagnosed 3 years following EOC. The 3-, 5- and 10-year incidence of BC was 5.6%, 9.5% and 33.3%. Annual mammography was performed in 43% and MRI in 34%. Twenty-eight (15%) women underwent risk-reducing mastectomy (RRM). There was no statistically significant difference in BC screening between women with, and without, a prior BC. BC was most commonly detected on mammogram. Three (17%) women had occult BC at the time of RRM. Nine (50%) had DCIS, and 8 (44%) had stage I/II BC. Median 5- and 10-year survival was 68% and 43% and was comparable between groups. CONCLUSIONS: Ten percent of women developed BC after EOC. The incidence of BC following EOC in BRCA carriers increases over time, and surveillance is recommended given their enhanced survival of EOC. Timely genetic testing for women with EOC is imperative to better triage BC screening resources and treatment.

Central effects of insulin detemir on feeding, body weight, and metabolism in rats.

Insulin detemir (DET) is a basal insulin analog that, in contrast to other long-acting forms of insulin, has significant weight-gain-sparing effects in diabetic patients. We hypothesized that this effect of DET may be due to its enhanced catabolic action in the central nervous system. We investigated the long-term effects of single third ventricular (3V) microinjections of equimolar doses of DET and regular insulin in normal male rats on feeding, body weight, energy expenditure (EE), and respiratory quotient (RQ). Also, in acute testing, we assessed the ability of lower doses of DET to alter feeding, EE, and RQ when microinjected directly into the paraventricular nucleus (PVN). The anabolic peptide ghrelin served as a positive control in acute testing. 3V administration of both DET (0.5-2.0 mU) and regular insulin (2.0-8.0 mU) significantly reduced feeding and body weight over 48 and 120 h, respectively, with DET yielding greater inhibitory effects. DET also stimulated greater elevations of EE and reductions of RQ over 72 and 48 h postinjection, respectively. In acute (4 h) testing, microinjections of DET (0.5 mU) into the PVN reduced feeding, increased EE, and reduced RQ, while ghrelin (100 pmol) had the opposite effects. When administered sequentially into the PVN, DET (0.25 and 0.5 mU) reversed ghrelin-induced feeding, EE, and RQ effects. These data support the notion that the weight-sparing effect of DET is at least in part based on its central catabolic action and that enhanced EE and reduced RQ may participate in this effect.

Blockade of the GLT-1 Transporter in the Central Nucleus of the Amygdala Induces both Anxiety and Depressive-Like Symptoms.

Depression has been associated with abnormalities in glutamatergic neurotransmission and decreased astrocyte number in limbic areas. We previously demonstrated that global and prefrontal cortical blockade of the astrocytic glutamate transporter (GLT-1) induces anhedonia and c-Fos expression in areas that regulate anxiety, including the central amygdala (CEA). Given the role of the amygdala in anxiety and the high degree of comorbidity between anxiety and depression, we hypothesized that GLT-1 blockade in the CEA would induce symptoms of anhedonia and anxiety in rats. We microinjected the GLT-1 inhibitor, dihydrokainic acid (DHK), into the CEA and examined effects on intracranial self-stimulation (ICSS) as an index of hedonic state, and on behavior in two anxiety paradigms, elevated plus maze (EPM) and fear conditioning. At lower doses, intra-CEA DHK produced modest increases in ICSS responding (T0). Higher doses resulted in complete cessation of responding for 15 min, suggesting an anhedonic or depressive-like effect. Intra-CEA DHK also increased anxiety-like behavior such that percent time in the open arms and total entries were decreased in the EPM and acquisition of freezing behavior to the tone was increased in a fear-conditioning paradigm. These effects did not appear to be explained by non-specific changes in activity, because effects on fear conditioning were assessed in a drug-free state, and a separate activity test showed no significant effects of intra-CEA DHK on locomotion. Taken together, these studies suggest that blockade of GLT-1 in the CEA is sufficient to induce both anhedonia and anxiety and therefore that a lack of glutamate uptake resulting from glial deficits may contribute to the comorbidity of depression and anxiety.

Exploring the role of central astrocytic glutamate uptake in ethanol reward in mice.

BACKGROUND: Alcoholism is associated with specific brain abnormalities revealed through postmortem studies, including a reduction in glial cell number and dysregulated glutamatergic neurotransmission. Whether these abnormalities contribute to the etiology of alcoholism, are consequences of alcohol use, or both is still unknown. METHODS: We investigated the role of astrocytic glutamate uptake in ethanol (EtOH) binge drinking in mice, using the "drinking in the dark" (DID) paradigm by blocking the astrocytic glutamate transporter (GLT-1) with intracerebroventricular (ICV) administration of dihydrokainic acid (DHK). To determine whether astrocytic glutamate uptake regulates the conditioned rewarding effects of EtOH, we examined the effects of ICV DHK on the acquisition and expression of EtOH-induced conditioned place preference. RESULTS: Blocking central astrocytic glutamate uptake selectively attenuated EtOH binge drinking behavior in mice. DHK did not alter the acquisition or expression of preference for EtOH-associated cues, indicating that reduced astrocytic glutamate trafficking may decrease binge-like drinking without altering the conditioned rewarding effects of EtOH. CONCLUSIONS: Several alternative conclusions are plausible, however, interpreting these data in the context of the human literature, these findings suggest that the reduction of glia in the alcoholic brain may not be a predisposing factor to developing alcoholism and could be a consequence of EtOH toxicity that decreases excessive EtOH intake.

Blockade of astrocytic glutamate uptake in the prefrontal cortex induces anhedonia.

Major depression is associated with both dysregulated glutamatergic neurotransmission and fewer astrocytes in limbic areas including the prefrontal cortex (PFC). These deficits may be functionally related. Notably, astrocytes regulate glutamate levels by removing glutamate from the synapse via the glutamate transporter (GLT-1). Previously, we demonstrated that central blockade of GLT-1 induces anhedonia and c-Fos expression in the PFC. Given the role of the PFC in regulating mood, we hypothesized that GLT-1 blockade in the PFC alone would be sufficient to induce anhedonia in rats. We microinjected the GLT-1 inhibitor, dihydrokainic acid (DHK), into the PFC and examined the effects on mood using intracranial self-stimulation (ICSS). At lower doses, intra-PFC DHK produced modest increases in ICSS thresholds, reflecting a depressive-like effect. At higher doses, intra-PFC DHK resulted in cessation of responding. We conducted further tests to clarify whether this total cessation of responding was related to an anhedonic state (tested by sucrose intake), a nonspecific result of motor impairment (measured by the tape test), or seizure activity (measured with electroencephalogram (EEG)). The highest dose of DHK increased latency to begin drinking without altering total sucrose intake. Furthermore, neither motor impairment nor evidence of seizure activity was observed in the tape test or EEG recordings. A decrease in reward value followed by complete cessation of ICSS responding suggests an anhedonic-like effect of intra-PFC DHK; a conclusion that was substantiated by an increased latency to begin sucrose drinking. Overall, these results suggest that blockade of astrocytic glutamate uptake in the PFC is sufficient to produce anhedonia, a core symptom of depression.

N-arachidonoyl-serotonin in the basolateral amygdala increases anxiolytic behavior in the elevated plus maze.

CB(1) receptors in the amygdala have been shown to mediate learned and unlearned anxiety states, however, the role of amygdalar TRPV1 receptors remains unclear. In the present study we investigated the potential anxiolytic action of intra-basolateral amygdala (BLA) infusion of N-arachidonoyl-serotonin (AA-5-HT), a dual blocker of the endocannabinoid-inactivating enzyme, fatty acid amide hydrolase (FAAH), and a TRPV1 antagonist. Varying doses of AA-5-HT (0-0.5 nmol) were administered into the BLA prior to elevated plus maze testing. AA-5-HT significantly increased both time spent and number of entries into the open arms. Next, to determine whether the anxiolytic effects were the result of blocking FAAH, TRPV1, or whether a combined action was required, rats were given intra-BLA infusions of either 0.25 nmol AA-5-HT, 1.0 nmol capsazepine (CZP, a TRPV1 antagonist), 0.01 µg URB597 (a selective FAAH inhibitor), or vehicle. Again, AA-5-HT increased the time spent in the open arms as well as the number of open arm entries. In contrast, CZP and URB597 did not reliably alter plus maze performance. We then investigated the effects of co-administration of CZP (1.0 or 10.0 nmol) and URB597 (0.01 or 0.1 µg). At lower doses, co-injections significantly increased both open arm entries as well as the time spent in the open arms, compared to vehicle or either compound alone. While co-administration of the higher doses had no significant effect when compared to either vehicle or CZP treatment, we did observe that open arm activity was elevated in rats receiving combined CZP-URB597 treatment compared to URB597 alone. Overall, our findings indicate that simultaneous FAAH activity and TRPV1 activation are important with respect to the expression of unconditioned fear as mediated within the BLA.

Anorexigenic action of nitric oxide synthase inhibition in the raphe nuclei.

The present report examined the effects of midbrain raphe nuclei injections of nitric oxide synthase inhibitors NG-nitro-L-arginine methyl ester (L-NAME) and 7-nitroindazole (7-NI) on eating behavior. L-NAME (5-500 pmol) and 7-NI (2-200 pmol) were administered into either the dorsal or median raphe nucleus. Both nitric oxide synthase inhibitors decreased food intake in adult male Sprague-Dawley rats when injected into either raphe site. Further, eating elicited by dorsal and median raphe injections of the 5-HT1A agonist 8-OH-DPAT (0.8 nmol) was attenuated by L-NAME or 7-NI pretreatment. Our findings indicate that nitric oxide acts within the raphe to alter food intake. The inhibitory effects of L-NAME and 7-NI on eating elicited by 8-OH-DPAT further suggest that nitric oxide and 5-HT systems interact in the control of food intake.

CD-1 and Balb/cJ mice do not show enduring antidepressant-like effects of ketamine in tests of acute antidepressant efficacy.

RATIONALE: In patients, ketamine is a fast-acting antidepressant that can induce long-lasting symptom relief. Similar rapid effects have been reported in rodents, but reports of lasting effects are limited. OBJECTIVES: We sought to extend past findings by examining dose-response curves that overlap with the individual doses previously reported to induce lasting effects in rodents and determining whether effects generalize to the tail suspension test (TST) and Balb/cJ mice. METHODS: Using common tests of antidepressant efficacy we first confirmed our ability to detect the effects of desipramine, a well-characterized antidepressant drug. Next, we sought to determine whether two non-competitive NMDA antagonists, ketamine and MK-801, had long-lasting antidepressant-like effects in CD-1 mice, a strain that has often been used to demonstrate the short-term antidepressant-like effects of ketamine. Finally, we examined the short- and long-term effects of ketamine in a mouse strain that is more sensitive to antidepressant-like effects, Balb/cJ mice. RESULTS: In CD-1 mice, desipramine treatment yielded significant short-term antidepressant-like effects in the TST and the forced swimming test (FST). However, no significant enduring effects of ketamine or MK-801 were observed 1 week later. Short-term effects of ketamine in the TST were observed in Balb/cJ mice, but lasting effects were absent 1 week later. CONCLUSIONS: Although the TST and FST have been widely used to detect antidepressant-like effects in mice, they do not appear to be sensitive to long-lasting antidepressant-like effects of ketamine in mice and, therefore, do not model the therapeutic effects of ketamine that have been reported in humans with major depression.

Hypothalamic paraventricular 5-hydroxytryptamine inhibits the effects of ghrelin on eating and energy substrate utilization.

Ghrelin microinjections into discrete regions of the hypothalamus, including the paraventricular nucleus (PVN), stimulate eating and promote carbohydrate oxidation, effects similar to PVN microinjection of neuropeptide Y (NPY). We have also reported that NPY's orexigenic and metabolic effects are antagonized by pretreatment with 5-hydroxytryptamine (5-HT) or 5-HT receptor agonists. In order to determine whether 5-HT also inhibits ghrelin's orexigenic and metabolic actions, the present study examined the effects of 5-HT pretreatment on ghrelin-induced alterations in eating and energy substrate utilization following direct injections into the hypothalamic PVN. Both 5-HT (5-20 nmol) and ghrelin (100 pmol) were administered at the onset of the dark cycle. Food intake was measured 2h postinjection. A separate group of rats (n=8) was injected with 5-HT paired with ghrelin and respiratory quotient (RQ; VCO(2)/VO(2)) was measured over 2h using an open circuit calorimeter. PVN injections of ghrelin increased food intake and increased RQ, reflecting a shift in energy substrate utilization in favor of carbohydrate oxidation. 5-HT effectively blocked the effects of ghrelin on both food intake and RQ. We then administered the 5-HT(2A/2C), receptor agonist, DOI, immediately prior to ghrelin. Similar to 5-HT, PVN DOI blocked ghrelin-induced eating and inhibited the peptide's effect on substrate utilization. These data are in agreement with other evidence suggesting that ghrelin functions as a gut-brain peptide in the control of food intake and energy metabolism, and indicate that 5-HT acts within the PVN to modulate ghrelin's orexigenic and metabolic signaling.